In the field of this invention it is known that in a distributed processing system having a plurality of nodes, while a processing node can fail in an arbitrary way, it is necessary to assure that a single faulty fail-uncontrolled processing node does not disrupt communication among fault-free processing nodes. In order to achieve this objective it is known to use either                (a) a fully connected network topology, or        (b) a multi-drop transmission line topology, or        (c) a star topology containing an intelligent central distribution unit, or        (d) a multi-access topology with an ‘anti-jabbering’ unit in the form of a bus guardian at the outgoing network interface of each processing node.        
However, these approaches have the disadvantages that:                (a) a fully connected network topology involves high cost, and an unfeasible network structure;        (b) a multi-drop transmission line topology requires a receiver for every multi-drop transmission channel;        (c) a star topology containing an intelligent central distribution unit requires high complexity in the distribution unit, increasing susceptibility to faults;        (d) in a multi-access topology with an ‘anti-jabbering’ unit in the form of a bus guardian at the outgoing network interface of each processing node, the bus guardian is susceptible to spatial proximity faults, and potential functional dependency between the bus guardian and the communication unit within the processing node.        
A need therefore exists for a scheme for interconnecting processing nodes in a distributed system wherein the abovementioned disadvantages may be alleviated.